Field of the Invention
The present invention relates to replenishment control of toner.
Description of the Related Art
An electrophotographic image forming apparatus develops an electrostatic latent image in a developing unit and forms a toner image in accordance with image data input in the image forming apparatus. In this image forming apparatus, since toner in the developing unit is consumed as the toner image is formed, a configuration to suitably replenish the developing unit with toner contained in a container that is detachably attached to the image forming apparatus has been proposed.
Further, since density of the toner image developed by the developing unit is changed depending on an amount of toner accumulated in the developing unit, the amount of toner replenished to the developing unit from the container is to be controlled with high accuracy.
Therefore, a related art image forming apparatus determines the amount of toner to be replenished such that the amount of toner in the developing unit becomes a target amount by predicting an amount of toner consumed from the developing unit (i.e., toner consumption) when a toner image is formed in accordance with image data. Here, since the toner consumption is a theoretical value determined by calculation, some errors exist between actual toner consumption actually consumed from the developing unit and the determined toner consumption described above. That is, there is a possibility that the amount of toner in the developing unit does not become the target amount even if the toner corresponding to the toner consumption determined as described above is replenished.
This is because the amount of toner replenished to the developing unit from the container fluctuates depending on the amount of toner contained in the container. That is, this is because the amount of toner replenished to the developing unit from the container by one replenishing operation decreases each time the replenishing operation of the toner to the developing unit from the container is performed.
Then, Japanese Patent Laid-Open No. 4-304486 discloses a toner replenishing device configured to correct an amount of toner to be replenished in accordance with toner consumption using a correction amount calculated in accordance with an amount of toner in the developing unit.
However, the toner replenishing device disclosed in Japanese Patent Laid-Open No. 4-304486 has an issue that the amount of toner in the developing unit is not able to be controlled to a target amount once the container is replaced. This is because the amount of toner replenished to the developing unit from the container in a single replenishing operation is changed once the container is replaced.